Vibratory device for cleaning dentures and the like



' Oct. 6, 1964 P. D. GEORGE 3,151,846

VIBRATORY DEVICE FOR CLEANING DENTURES AND THE LIKE Filed Sept. 21, 1962i l 24" e:-

..n I INVENTOR.

PETER D. GEORGE AT TOR N EYS United States Patent 3,151,846 VIBRATORYDEVICE BOB CLEANING DENTURES AND TEE LIKE Peter 1). George, Quincy,Mass. (156 Crabtree Road, Squantum, Mass.) Filed Sept. 21, 1962, Ser-No. 225,256 1 Claim. (Cl. 25991) This invention relates generally tovibratory cleaning devices and more particularly concerns a new andimproved tank cleaning apparatus for removing surface impurities fromvarious types of articles such as denture plates and the like.

While it is well known in the art to clean the surfaces of all types ofsolid articles by submerging them in a suitable liquid and thenintroducing high frequency vibrations to the liquid, all of the devicesheretofore available have been relatively complicated instruments,sensitive to high temperatures and generally quite expensive.Furthermore, these devices, by reason of their specialized design, donot readily lend themselves to popular use being primarily designed andintended for industrial applications.

Accordingly, it is an object of the present invention to provideimprovements in vibratory cleaning devices.

Another object of this invention is to provide an efficient, low-cost,vibratory tank cleaning device for use in removing surface impuritiesfrom various types of articles particularly artificial dentures.

Still another object of this invention is to provide a vibratory tankcleaning device of simple, rugged constructoin having utility in bothindustrial and home applications.

More particularly, this invention features a vibratory cleaningapparatus comprising a vessel for containing a liquid cleaning medium inwhich the articles to be cleaned are submerged, mounted to the wall ofthe vessel is a novel transducer head employing a number of concentricannular shoulders to generate and amplify vibrations through thecleaning medium when the transducer driving apparatus is actuated. Thedriving mechanism for the transducer comprises a coil which surrounds anelongated metallic rod connected fast to the transducer. Upon theapplication of an A.C. current to the coil, the rod will be vibratedaxially at a frequency corresponding to the current applied to the coil.The vibrating rod thus transfers its vibrations to the transducer whichin turn causes the liquid cleaning medium to be cavitated, resulting ina highly efficient cleaning action.

In a modification of the invention, the driving mechanism is providedwith adjustment means for varying the vibrating action of thetransducer.

But these and other features of the invention, along with furtherobjects and advantages thereof, will become more fully apparent from thefollowing and detailed description, taken in connection with theaccompanying drawings in which:

FIG. 1 is a view in perspective of a preferred embodiment of theinvention,

FIG. 2 is a sectional view in side elevation of the device of FIG. 1,

FIG. 3 is a perspective view of the transducer element employed in theinvention, and

FIG. 4 is a sectional view in side elevation of a modification of theinvention.

Referring now to FIGS. 1 to 3 of the drawings, the reference charactergenerally indicates a vibratory cleaning apparatus having a lowerhousing 12 and an upper cup-shaped vessel 14 adapted to contain a liquidcleaning medium 16 such as water or other suitable liquid. in practice,the vessel 14 is formed from a suitable mate- "Ice rial such as moldedplastic, typically polyethylene, and is provided with a marginal lip 18which is adapted to lock in snapping engagement with a cover 22 whichmay also be fabricated from polyethylene, if desired. The hous ing 12may be formed from aluminum or the like and, as shown, has a lowerannular flange 24 which engages the marginal edge of a plate 26 by meansof a resilient annulus 28 which is split about its inner periphery forclamping engagement with the flange 24 and the edge of the plate 26.

Mounted within the housing 12 is a solenoid 31 having a coil 32 woundabout a vertical copper tube 34. The tube 3-4 is mounted within arectangular metal frame 36 which surrounds the coil 32. The bottom wallof the frame 36 is provided with a circular opening 33 having a diameterslightly smaller than the tube 34- so as to form an annular shoulderupon which is seated a collar 4i). The collar 49 provides a limit stopfor a cylindrical core or stem 42 which is received in the tube 34. Acoil spring 44 is mounted within the collar and has its upper endextending slightly above the upper end of the collar for reasons thatwill presently appear. The coil 32 may be connected to an alternatingcurrent power source by means of leads 46 passing out of the housing 12through a grommet 48.

The stem 42 typically is fabricated from a suitable ferrous materialsuch as chrome steel or the like and at its upper end supports thevessel 14. As best shown in FIG. 2, the stem engages the vessel 14 bymeans of a screw 50 passing through the center of a transducer head 52,through the bottom wall of the vessel 14, through a. washer 54 and intothe tapped upper end of the stem 42. The transducer head 52 preferablyis fabricated from stainless steel or the like and has a circularconfiguration characterized by a plurality of concentric annular ribs56. In the preferred embodiment, the transducer has a diameter of 1%inches with a convex upper surface which, in cooperation with theannular ribs, amplifies and transmits vibrations into the cleaningmedium 16 when the coil 32 is energized with an alternating current.

It will be understood that when the coil is energized, the stem 42 willreciprocate at the same frequency as the current in the coil. Thedisplacement of the stem will be of relatively small order but will besufiicient to generate effective vibrations in the vessel 14. Althoughnormally operated at cycles obviously the frequency at which thetransducer will be actuated may be varied over a wide range according tothe desired effect which is to be achieved. By providing the spring 44,the stem 42 is prevented from coming into direct striking contact withthe collar 40 thereby maintaining a low noise level during operation ofthe device.

It will be appreciated that the device described above may be fabricatedat a relatively low cost yet provides a simple, rugged and efiicientcleaning unit. The invention has particular utility for homeapplications and has been found to be effective in cleaning such itemsas denture plates, jewelry such as broaches, rings and the like, andother similar articles. In practice, it has been found that water with aslight amount of detergent added is an excellent cleaning mediumalthough other liquids may also be employed depending upon theparticular article which is to be cleaned. It will be understood thatthe cleaning effect is achieved by cavitations in the cleaning mediumdeveloped by rapid vibration of the transducer head. As is well known incleaning devices of this type, the cavitation is the result ofrelatively high energy vibrations transmitted through the liquid withthe result that a very great number of minute cavities are formed which,when they strike an article within the liquid, collapse and releasetheir energy with an implosive force which r; Gt produces the cleaningaction. It has been found that in using the particular device, it shouldbe operated for a minute or so before introducing the articles to becleaned. It has been found that a certain amount of deaerating of theliquid is necessary before the cleaning action can be achieved.Therefore, by running the device fora short while all of the free oxygenwithin the liquid will be liberated so as to leave a substantiallydegassified liquid. While plain water may be used as the cleaningmedium, the usual results are that only loose particles are freed fromthe articles being processed, whereas the addition of a small amount ofdetergent will produce complete cleaning of the article. It has alsobeen found that optimum agitation is achieved at a frequency of 120cycles. Obviously, the frequency may be varied according to theparticular cleaning medium and according to the physical characteristicsof the article which is being cleaned.

Referring now more particularly to FIG. 4, there is illustrated amodification of the invention and, in this I embodiment, a cup 60 ispivoted for vibratory movement to a permeable iron arm 62. The arm iscoupled to the cup by means of a stub shaft 64 fastened to a washer 66which in turn is connected to a transducer head 68 of a configurationsimilar to that of the principal embodiment. The arm 62, as shown, ispivotally connected at one end to a vertical leg of a laminated solenoidbody 70 which carries a central coil 72. The coil 72, in turn, is woundabout a coaxial tube 74 which carries a coil spring 76 mounted snuglytherein. The upper end of the spring 76 bears against the lower portionof the arm 62 so as to provide a resilient cushion for the arm when theassembly is actuated. An adjustment screw 78 is threaded to a circularopening formed at the bottom of the solenoid body 70 and may be raisedor lowered so as to vary the pressure of the spring 76 against the arm62. For this purpose, an axial opening 80 has been formed through thebottom portion of the apparatus to provide access to the adjustmentscrew. The solenoid body shown is mounted on a plate 82 which in turn isdisposed below the pad and has mounted thereto a housing 88 similar inshape to that of the principal embodiment. The coil 72 may be energizedthrough a lead 90 which may connect to a power source of fixed frequencyor to a variable frequency generator 92. By connecting the cleaningdevice to the variable frequency generator, a wide range of operatingconditions may be met. It will be understood that with differentarticles to be cleaned and with different cleaning mediums optimumcleaning action will be best provided at a certain frequency. By havinga variable frequency source, the apparatus is considerably more flexiblethan would be the case when only one frequency is available.

In operation, when the coil 72 is energized, the arm 62 will oscillateabout its pivot pin 94 causing the transducer 68 to vibrate at thefrequency of the energizing current. The coil spring 76 serves tocooperate with the alternating magnetic field to vibrate the arm 62without its striking the solenoid body 40.

While the invention has been described with particular reference to theillustrated embodiments, it will be understood that numerousmodifications thereto will appear to those skilled in the art. It willalso be understood that the above description and accompanying drawingsshould be taken as illustrative of the invention and not in a limitingsense.

Having thus described my invention, what I claim and desire to obtain byLetters Patent of the United States is:

A cleaning device, comprising a receptacle of resilient material adaptedto contain a liquid cleaning medium and articles to be cleaned, a rigiddisc shaped metallic head fixed centrally on a bottom wall of saidreceptacle and below the level of said medium, said head having a convexouter surface formed with a plurality of evenly spaced concentricannular ribs separated by a plurality of evenly spaced concentricannular grooves adapted to cavitate said cleaning medium on vibrationthereof, a moveable core of magnetically attractive material rigidlyconnected to said head and said receptacle and extending through saidwall, a coil having an axial opening formed therethrough for receivingone end of said core and a resilient element mounted within said openingadjacent said one end of said core, said core being adapted to vibrateaxially upon the application of an alternating current to said coil.

References Cited in the file of this patent UNITED STATES PATENTS2,356,004 Price Aug. 15, 1944 2,543,818 Wilcox Mar. 6, 1951 2,724,393Heise Nov. 22, 1955 2,776,558 Vang Jan. 8, 1957 2,815,193 Brown Dec. 3,1957 2,875,989 Toulmin Mar. 3, 1959 2,906,111 Long et al Sept. 29, 1959FOREIGN PATENTS 666,244 Great Britain of 1952 1,055,493 France Oct. 14,1953

